1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a layout of liquid crystal display (LCD) panels and a size of a mother substrate to maximize the substrate efficiency.
2. Discussion of the Related Art
With the growth of the information society, demands for various display devices has increased. Accordingly, many efforts have been made to research and develop various flat display devices, for example, a liquid crystal display (LCD) device, a plasma display panel (PDP), an electroluminescent display (ELD) and a vacuum fluorescent display (VFD), and some species of the flat display devices are already applied to displays of various equipments.
Among the various flat display devices, the LCD device has been most widely used due to the advantageous characteristics of compact size, thin profile, and low power consumption, whereby the LCD device substitutes for a Cathode Ray Tube (CRT). In addition to the mobile type LCD devices such as a display for a notebook computer, the LCD devices have been developed for computer monitors and televisions to receive and display broadcasting signals. Especially, as the LCD devices are used for the televisions, it is trending toward various and large sizes in the LCD devices.
In general, the LCD device includes an LCD panel for displaying an image and a driver for supplying a driving signal to the LCD panel. In addition, the LCD panel includes first and second substrates bonded to each other, and a liquid crystal layer formed between the first and second substrates.
The first substrate (referred to as a TFT array substrate) includes a plurality of gate lines arranged along a first direction at fixed intervals, a plurality of data lines arranged along a second direction perpendicular to the first direction at fixed intervals, a plurality of pixel electrodes arranged in a matrix-type configuration within pixel regions defined by the gate and data lines, and a plurality of thin film transistors transmit signals from the-data lines to the pixel electrodes in accordance with signals supplied to the gate lines.
The second substrate (referred to as a color filter array substrate) includes a black matrix layer that prevents a light leakage from portions of the first substrate except at the pixel regions, an R/G/B color filter layer for displaying various colors, and a common electrode for producing an image. In an IPS mode LCD device, the common electrode is formed on the first substrate, and an overcoat layer is formed on the second substrate.
When manufacturing the LCD devices, a plurality of LCD panels are formed on one mother substrate. That is, a plurality of LCD panel areas are designed in a first mother substrate, wherein each LCD panel area includes a thin film transistor array. Also, a plurality of LCD panel areas are designed in a second mother substrate, wherein each LCD panel area includes a color filter array. Then, a sealant is formed in the periphery of each LCD panel area formed on any one of the first and second mother substrates. Thereafter, the first and second mother substrates are bonded to each other, and the bonded substrates are cut into the unit LCD panel areas, thereby manufacturing the LCD devices.
The method for manufacturing the LCD device is classified into a liquid crystal injection method and a liquid crystal dispensing method.
In the liquid crystal injection method, the two substrates are bonded to each other, and then the bonded substrates are cut into the unit LCD panel areas. Thereafter, liquid crystal is injected to each LCD panel. Meanwhile, if applying the liquid crystal dispensing method, liquid crystal is appropriately dispensed on each LCD panel area of the first or second mother substrate, and then the first and second mother substrates are bonded to each other. Thereafter, the bonded substrates are cut into the unit LCD panels.
However, the liquid crystal injection method requires a long time for injection of liquid crystal, and spends a lot of liquid crystal. Accordingly, the large-sized LCD device generally uses the liquid crystal dispensing method. A method for manufacturing the LCD device according to the liquid crystal dispensing method will be explained as follows.
FIG. 1 is a block diagram of a method for manufacturing an LCD device according to the related art.
First, a plurality of LCD panel areas are designed in first and second mother substrates. Then, a thin film transistor array including a gate line, a data line, a thin film transistor, and a pixel region is formed in each LCD panel area of the first mother substrate (S11), and a first alignment layer is formed on an entire surface of the first mother substrate, and a rubbing treatment is performed thereto (S12). Then, a color filter array including a black matrix layer, a color filter layer, and a common electrode is formed in each LCD panel area of the second mother substrate (S15), and a second alignment layer is formed on an entire surface of the second mother substrate, and a rubbing treatment is performed thereto (S16).
In an IPS mode LCD device, a thin film transistor array including a gate line, a data line, a thin film transistor, a pixel region, and a common electrode is formed in each LCD panel area of the first mother substrate, and a color filter array including a black matrix layer, a color filter layer, and an overcoat layer is formed in each LCD panel area of the second mother substrate.
Then, the first and second mother substrates are cleaned (S13, S17). The cleaned first mother substrate is loaded into a liquid crystal dispenser (LC dispenser), and liquid crystal is dispensed on the LCD panel areas of the first mother substrate (S14). Then, the cleaned second mother substrate is loaded into Ag and sealant dispensers, whereby Ag dots are formed on each LCD panel area (S18), and a sealant is formed in the periphery of each LCD panel area (S19).
Thereafter, the first and second mother substrates are loaded into a bonding apparatus, whereby the first and second mother substrates are bonded to each other. Then, the bonded first and second substrates are loaded into a curing apparatus, whereby the sealant is cured (S20). After that, the bonded first and second mother substrates having the cured sealant are loaded into a cutting apparatus, whereby the substrates are cut into the LCD panels (S21). Then, the cut LCD panels are polished, and then is finally tested (S22). Although not shown, a driving circuit, a polarizing film, and a backlight are provided to each LCD panel, thereby completing the LCD device.
On manufacturing the LCD panels, the efficiency of mother substrate depends on the arrangement of LCD panels having the various sizes (models) on the mother substrate. Also, since the LCD panel is manufactured by the several steps, the size of the mother substrate is limited due to the size in each apparatus for manufacturing the LCD panel.
Accordingly, after selecting the main model of the LCD panel, the layout is designed based on the arrangement of the main models on the mother substrate. According to the design of layout, the optimal size of the mother substrate is determined.
However, the efficient size of mother substrate, which can improves the efficiency of mother substrate in consideration of the layout for arranging the LCD panels, has not been proposed. Also, if arranging the plurality of LCD panels of the same size (model) on one mother substrate, the efficiency of mother substrate is lowered. This problem becomes more serious as the size of LCD panel becomes larger.